I'm pretty sure a lot of this stuff are arbitrary decisions that sites make when they implement passkey support and you never know where it will work. Also some sites likely don't care about fixing it since they think they deliberately are "improving security" or they just don't care. So I'd say it's an ugly mess. I wish it would work though.
Well, see here: https://github.com/keepassxreboot/keepassxc/issues/10374
I'm pretty sure a lot of this stuff are arbitrary decisions that sites make when they implement passkey support and you never know where it will work. Also some sites likely don't care about fixing it since they think they deliberately are "improving security" or they just don't care. So I'd say it's an ugly mess. I wish it would work though.